Skip to main content

local variable scope

Method- local variable

Local variables inside a method is not accessible outside the method.

Eg:

def method
  x = 2
end

 puts x

This will result in an error .

To access variables outside a method. You need to pass in parameters/arguments into the method.

 x = ''
def method(x)
  x = 2
end

 puts method(x)

 However, in this case, x is still ' ' . The puts only print the return value of the method , which is 2. 
The method do not mutate the caller.

Local variable - block scope.

Local variable that sits outside a block is ACCESSIBLE to inside the block. While local variable that is initialize inside a block is NOT ACCESSIBLE outside the block.

Eg:

 x = "Hello"

 loop do
   puts x
   break
end

This is ok

Eg:

loop do 
   x = "Hello"
   break
end

 puts x

This will result in an error.

 PS: Please take note that IF statement is not considered a block. Therefore any variables initialized in an IF statement is accessible outside the method.



Labels:

Comments

Post a Comment

Popular posts from this blog

Problem Solving - Refactored

I am going to outline how I approach problem solving. The relative importance and the amount of effort/time required for each is stated as a percentage beside each topic. I borrowed some idea from George Polya's How to Solve It Thoroughly Understand the Problem (30%) When encountering hard problem , you need to deeply understand the problem at hand. Take a paper and list down all known facts and data and what the question is trying to find. Sketch out the problem if applicable. Visualize the problem in your head. A lot of times, we only have to understand the problem well, then the solution will obvious. Have a Plan (20%) You need to have an outline of how you are going to tackle the problem. You need to have a logical pathway that will ultimate produce outcome (nothing to do with coding syntax yet). Without a plan, you are just randomly poking around and got lucky. No hard problem ever gets solved without a plan. Plan using pseudo-code, pen & paper or flowchart. Use wh...
5 comments
Read more

Sharing my Weakness

It makes sense to know about your weakness and do something about it. Here are my known weaknesses uncovered during my time in Launch School. 1. I don't like to refactor my code   - Your first draft will not be perfect. It works but it may not be efficient/readable/best practices. You final code will almost always be better than your first draft. - It is easier to separate the task between writing code that works and refactor later to make it efficient/readable/best practices. - If you refactor your code often, over time you will discover your bad habits and change it. 2. I don't like to read other people's code - There are more good programming practices in other people than in you (especially for beginners like me). - To be good , you need to know more than one pathways to solve a programming problem (and there are always more than one way). Then you can judge their merit. - Reason for dislikes    1. It is considerably harder to read code than to write one (...
1 comment
Read more

My Burnout Experience

I want to share with you my experience of burning out. After registering with Launch School, I am extremely excited about my programming journey. I studied for 10 to 12 hours a day, memorizing fact, trying out practice problems, understanding programming concepts. It was fun and exciting and I love seeing myself growing from nothing in programming to something more. After about 3 months, thing starts to change. I started noticing myself paying less attention to details. I find myself skimming through the course material. I skip "Further Exploration" in the practice problem. I am more interested to study just to pass the assessment rather than truly mastering the concept. It was a gradual burning out process but I continue to study for 10 to 12 hours a day through sheer grit. It felt like doing house chore or working a day job that you don't like. One particular morning I woke up, and I remember this deep feeling of dread because I can anticipate that the next 10 to 1...
Post a Comment
Read more